1. Technical Field
The present invention relates to a method of manufacturing metal flakes, and, more particularly, to a method of manufacturing metal flakes using metal ink containing organic metal compounds.
2. Description of the Related Art
Among metals, silver (Ag), which is a precious metal, has been utilized for various purposes such as decorations, coins, tableware, electric home appliances, electric and electronic appliances, illumination, copiers, display electrodes, electromagnetic wave shielding, antibacterial actions and the like because of its special characteristics such as excellent electroconductivity, excellent antibacterial effects and the like. High-quality, low-cost products have recently become popular while electric and electronic products have become more varied and complex.
Currently, most metal particles such as silver particles, copper particles, nickel particles, aluminum particles and the like, which are mainly used in electric and electrical products, have a sphere or flake shape, and their shapes are selected depending on their uses. Generally, metal particles are prepared by an atomization method, electrochemical method or chemical reduction method. In this case, most of the fabricated metal particles have a spherical shape. The spherical metal particles obtained in this way are formed into metal flakes using a ball mill (U.S. Pat. No. 4,482,374, U.S. Pat. No. 4,859,241, U.S. Pub. No. 2006-0207385, JP-A-2007-84860 and JP-A-2007-254845) or using vacuum deposition (U.S. Pub. No. 2006-0117988 and JP-A-2005-281819). Such metal flakes can be widely used for conductive paste or conductive adhesives for electromagnetic wave shielding or electrodes requiring high conductivity, paint or ink requiring glosses or special colors, coloring pigments for cosmetics, and the like.
Meanwhile, the method of forming spherical metal particles into metal flakes using a ball mill, which is a most generally used technology, is advantageous in that it enables the mass production of metal flakes relatively easily, but is problematic in that technologies for preparing spherical metal particles are required in order to form metal flakes having uniform thickness and size and in that it is difficult to form metal flakes having various thicknesses and excellent surface gloss.
Further, to date, metal flakes have been formed using metal coating methods, such as plating, sputtering, plasma deposition, chemical vapor deposition (CVD), atomic layer deposition (ALD), electro-deposition, etc. This method is advantageous in that the metal flakes obtained by this method have uniform thickness and excellent gloss, but is problematic in that processes are complicated, costs are relatively high and the mass production of metal flakes is difficult.
Therefore, the method of manufacturing metal flakes according to the present invention is characterized in that it is easy to adjust the thickness and size of metal flakes, it is possible to form metal flakes having excellent particle characteristics such as conductivity, gloss and the like, and it is possible to mass-produce metal flakes using environmentally friendly and economical methods.